1. Cardiovascular System The Heart

2. Heart Facts
The cardiovascular system is composed of the heart and a _________system of vessels through which blood is circulated.
Hollow muscular organ
Tipped slightly so that a part of it sticks out and taps against the ______side of the chest (apex), which is what makes it seem as though it is located there.
During an average lifetime, the human heart will beat more than 2.5 billion times.
Beats over 100,000 times/day and 35 million times/year to pump blood around the body's 60,000 miles of blood vessels.
____pints of blood pump throughout your entire body with one single heartbeat.

3. External Structure of the Heart
Layers
Edocardium (inner layer)
Epicardium (outer layer)
Myocardium (middle layer)
_________________ - the protective membrane surrounding the heart
____________arteries – supply blood to the outside of the heart

4. External Structure

5. Internal Structure Septum Atria and ventricles
atria contract while the ventricles relax
ventricles contract while the atria relax.
____________________ (AV) Valves
Bicuspid (____________) Valve – between left atria and ventricle
Tricuspid Valve – between right atria and ventricle
__________________(SL) Valves
Pulmonary SL Valve – between right ventricle and pulmonary artery
Aortic SL Valve – between left ventricle and aorta
Ventricular ____________ - right and left ventricles are divided by a thick muscular wall
babies born with "hole in the heart“
Why problematic?
Septum

7. connect papillary muscles to AV valves
“heartstrings”

8. The Cardiac Cycle The events associated with one heartbeat.
A single cardiac cycle lasts ______ seconds
Described as the contraction and relaxation of the four heart chambers.
During relaxation, chambers fill with blood (_________________).
During contraction, chambers expel blood (_________________).
Heart Sounds
The first heart sound (______) occurs during ventricular contraction when the tricuspid and bicuspid valves (___valves) close.
The second heart sound (________) occurs during ventricular relaxation when the pulmonary and aortic valves (___ valves) close.

9. The walls of the left ventricle are ________ as it has to pump blood to all the tissues, compared to the right ventricle which only pumps blood as far as the _____.
Septum

11. Blood Pressure
Blood moves through circulatory system from areas of high pressure to low pressure. (Contraction of the heart produces the pressure.)
Blood Pressure is a measurement of the _______ that blood exerts against the inner walls of ______________.
120/80 is normal = systole/diastole
systolic pressure - The maximum pressure during ventricular contraction; systolic pressure is the peak arterial pressure.
diastolic pressure - The lowest pressure of blood in the arteries during ventricular relaxation (diastole); the arterial pressure drops.

12. Blood Pressure vs. Distance From Left Ventricle

13. Conduction System
Heart muscle cells contract without stimulation from the nervous system in a continuous, rhythmic pattern.
Contraction is initiated by the sinoatrial (SA) node (_______________________).
SA node is located in the right atrium
Cells of the SA node can reach threshold on their own
SA node initiates one action potential after another (~70-80 times/min)
Pathway of electrical impulse
Sinoatrial (SA) node
Atrioventricular (AV) node
Atrioventricular bundle (bundle of His)
Bundle branches
Purkinje fibers
There is a momentary delay as the ventricles fill before they contract

15. Electrocardiograms (ECG / EKG)
A recording of the electrical changes that occur within
the myocardium as the
heart contracts.
R vent cont
L vent cont
R atr cont

16. Electrocardiograms (ECG / EKG)
Atria repolarized
Ventricle depolarized
Heart relaxed
Ventricular walls
repolarize
AV node and
walls depolarize
Atrial walls
completely
depolarized
Atria repolarizes
Ventricle
depolarizes